Here's picture of solid turned 12ga slugs that Rob makes.
They are flat on one end and hollowpoint on other.
They can be shot either direction. Aluminum ones
are 346gr, brass 1080gr........If you need any
contact him. He, RIP, and others on AR are testing
them with different powders. I have gotten similiar brass
ones to 1900 in NEF with RMC case, with
140 gr the new RL-17. Ed

One of our testers, Bret in MN, got the BPI Sabot with
500gr Hornady .500 slug up to the good speed listed
on BPI"s loading sheet, using shotgun powders. I could
get them there with my loads using much larger amounts
of rifle powders. He tested 3.5" Federal plastic cases in
his Savage 210 with 3.5" chamber and the 28" heavy barrel
he put on. With 50gr of Longshot(max load for all modern
guns) he got 2550 fps, with 500gr in sabot. He use two
BPGS gas seals fitted together over the powder, then
a FS12 Flexseal wad, then a 1/4" cork wad, then the sabot.

Then a good strong roll crimp with drill/drillpress crimper.
This load is at mag shotgun pressures by case expansion
measurements and BPI's 46gr load tested at 12,500 psi.
He also did one with one BPGS and two Flexseals and had
200 fps less.He had tried other combinations seals/wads
and with same amount of powder and got lower yet.
He also went up with the powder, with seal/wads that worked
the best and got about 3000 fps, but the plastic cases
stuck and wouldn't eject easy. I will be testing same
seal and wad column in a few days, in my NEF with long
barrel to compare results.I thank Bret, he is a real
good experimenter and idea man. Everybody is trying
like crazy to get that 500gr saboted slug up to big
game gun velocities with shotgun powder and thanks to
BPI"s supply of the right components it has happened.Ed

Hey Ed! I got one! Let the games begin! The only thing I want to do for starters is get a 1000 grain slug like in your pic...

And yes, I know this is a 600 grain slug, but this is the cartridge type I'm looking for - all brass (converted .50 BMG) and a slug crimped on the end. Time to re-read all the info now! Here's mine alongside my limited-edition series 10/22:

First, do you know the status of Rob's stamped rims for the converted .50 BMG brass? I'd like to purchase some!

Second, I am interested in what I can load the NEF with when using long brass 3.85" case, with large primers? Like the one in this pic:

This is from Page 6 where you state this is RG's Jacketed 715 gr slug. I have some swaging equipment and can press my own jacketed slugs! What kind of load would you recommend for a 1000 gr slug / 3.85" full brass / large primer?

Lastly, when you say "large" primers, are you talking about SHOTGUN primers, Large RIFLE primers, or BMG primers?

Jerry- Nice looking NEF you have there.When I say large primers
I mean BMG primers. Rob can make rims or completed cases
and is selling them now. Rims aren't cheap, I think they are
about 5 dollars..Contact him at email given above.
Loads -With long case, bmg primers, you can use 240 grains
of slow HBMG powder.Start at 240 and if it extracts ok, work up.
Always fill up spage with seal and wads.Cushion wad is good.
Here is a Rob project that will make you drool.
Rob on AR is building a 12GA FH double on a Zabala Double
10 gauge frame. It has the Greener crossbolt. He cut off
barrels to make a 4" long monoblock double to screw a
pair of heavy 12ga rifled Pacnor barrels into. He reamed out
monoblock section and threaded it. His barrels are
1.116" at the breach, .97" at muzzle and 22" total length.
Barrels threaded into monoblock with a 15/16" x 32 thread.
In the pics it is partly done and he will put in the ribs
and integral sight rib and regulate for accuracy.
It will be about 14.5 lbs when done he says.Ed

Some more BPI seal and sabot testing.
First of all both Bret and I have heavy tight fit barrels
and his barrel on the Savage is faster twist so it took
him 50 gr of Longshot to get what BPI got with
looser barrels and slow twist at 46 gr of Longshot.
For non heavy barreled guns only go to 46 gr.
I did a bunch of tests in my NEF long barrel with long
chamber. My store didn't have any 500gr .500" XTP slugs
so I used some 420gr .512" dia lead Great plains in the
BPI sabot. Using 2 BPGS powder seals, a BPI Flexseal, a
cork wad in 3.5" new Federal cases, roll crimped, I got
2800 fps with 420gr slug. I tried 4 other powder seals,
2 cards, a Remington, a Win, and a odd one, all with the
Flexseal and lost velocity. I fixed up my crimper so it would
roll the plastic down and over inside edge of sabot, as before
it would turn plastiC in too sharp and get some of the crimp
outside the sabot top. If sabot was too low so that the plastic
crimp went clear down to the slug I got high pressure signs.
I also did same loads in used 3.5" REM cases ok.
Now, I thought I should have more velocity, so I swaged the
.512" 420GR slug down to .500" like they say the sabot is for,
AND I GOT OVER A 120 FPS MORE. Everytime. I also used
Alliant Steel powder and got all the same results, using
60gr. It is easier on cases. I also substituted the doubled up
BPGS powder seals and the Flexseal with 520gr Lyman in
place of the seal and cushion on the WW12 wadcup the Lyman
fits in, with some RL-17 loads, of 150gr, and got over 200fps more
that the original WW12 wadcup gave with the Lyman.

Velocity secret is to have the perfect sealing setup with
slug/sabot combo that is NOT too tight. Only tight enough
to get accuracy. The cork seems to protect the sabot
base ok on the shotgun powder loads, and not needed
on the RL-17 loads, which is a easier accelerating powder
and without cork helps make room for the RE-17. I think I
will get increases in the brass RMC cases, with RE-17, with
the BPGS doubled and a Flexseal in place of cards and wads.
We will know soon.Ed

OK where do I get reasonably priced 50 BMG brass? I am obviously a huge DIY kind of guy and the only brass I can find online is in lots of 50 or more! I think perhaps 12-20 rounds is all I'd need for a fun range day! Wondering if you guys get your brass new or once-fired?

You probably wil lhave to get 50. We try to get unfired
with bullets pulled out. Some shops sell new.Did you get
set up to put rims on cases....If you get used
do a good job annealing.
Here is picture of the breach of 8ga FH NEF with
case in it, to show that the gun is strong enough
for 8ga. I was a 10ga NEF. Has 29" effective barrel
length, and the internal expansion step at muzzle
for the ports that stops muzzle climb and reduces
recoil. Which along with thick pad and thumbhole
stock makes for easy shooting.Ed

Here is picture of a 12ga size drawn brass case that was
made back in the 80s. Case is for the CAWS weapon system.
Case is belted, and it and the gun operated at 25,000 psi.
Its bore size is between 12 and 10 ga size, but the od of
the drawn case would let it start in 12ga chambers, so
they added belt so it couldn't go all the way in
to regular shotguns. Notice the thick sides and corner
near the base.Heavy enough for 25,000 psi. They loaded
it with big buckshot and tested other projectiles also.
They had a plastic card over shot and filler and rolled
over brass mouth for crimp. Ed